merry Christmas. I need help!!!!!!

[tube-lover]

Dear all,

Today I received sample from japan's friend & he advise me use this type of resisters used in my Version II TDA1541a Non-oversampling DAC. He said this precision rersisters was very good in digital circuit. My Version I 1541a kit was used Dale in the digital circuit. My friend said he can offer a good price to me for the 5/1000 tor & 25ppm model.

pls click the website.

http://www.koaproducts.com/english/index_02.htm

model which I prepare used in my DAC Version II.

http://www.koaproducts.com/pdf/090-091-MFP.pdf

http://www.koaproducts.com/pdf/088-089-MF.pdf

The brown one in the photo was 5/1000 tor, blue one is 1/100 tor.

I hadn't any experience for this resisters.

pls advise

thx

thomas

[janneman]

What's the question?

Jan Didden

[Bill Fitzpatrick]

He wants to know which color is best. It's a shame they don't offer red ones which are my preference.

[tube-lover]

dear janneman ,

do U had any experience using this brand resisters??
Do U know the performance about this brand resisters??

my previous kit use dale metal film resisters, all 1% tor & 50~100PPM. But this brand was 5/1000 tor & 25PPM.
Better Spec than dale but performance?????? I don't know, so I ask diyers to help me. Hope can get some advise!

Japan suggest the I/V use carbon film & digital circuit use this type rersisters.


thx

thomas

[janneman]

Well, you must understand that I am a typical sceptic about "this resistor sounds best" or "this cap should have the plastic jacket removed to sound best".

There are so many components in a typical equipment that I find it very hard to believe that changing a few to other types will be audible (exceptions below). As can be read on various places on this board, there are many, many factors determining the perceived audio quality of a piece of equipment *other* than the sound itself. To mention a few: size, color, weight, price paid, your friends opinion, your expectations, etc.

On the case of resistors, unless you have a special piece of equipment, 2% tol should suffice. Every competently designed amplifier should be able to function according to spec with small variations in components. For example, transistor gain often varies over more than a factor of two. There are some exceptions: sometimes you need a specific ratio in a design to set a current gain or something. In such cases you may need two resistors with a certain ratio, and it is easiest just to get two .1% ones. But other than that, the tol (within reason) has no bearing on sound quality.

Resistors DO vary in noise between types. Again, the designer should take care that the amp doesn't need some unreasonable low noise resistors. Still, in input- and feedback resistors, for example, especially when higher that say 5k or so, low noise types *may* lower the measurable and ausible (ear-in-speaker) noise. Finally, resistors should be reasonably stable, for instance not change more than say 1% over 50 degrees temp change, which I think comes out to 200ppm/degree or something.

In analog stages, the resistor noise for example can directly turn up in the analog signal. I have no idea how this could ever happen in digital circuits. Digital circuits are known for the lack of resistors. I don't know to which digital circuits your friend refers to.

So, my answer would be: no, I have no experience with these specific resistors. But.... see above.

Jan Didden

[pburke]

for a high grade resistor, I generally use these:

http://www.texascomponents.com/Tx2352a.pdf

but that may be out of the price range for your kit. They may have decent volume pricing, but you're still looking at a few dollars a piece.

don't know anything about the brand you're asking about.

Peter

[tube-lover]

Dear janneman & pburke,

thanks for your opinions & share experience to me.

BTW, How about the precision series of philips.


http://www.texascomponents.com/Tx2352a.pdf

This type of resistors will be very good in the I/V resistors of the DAC. Per DAC only use 2 pcs, I think will acceptable for them although in high price.

but, dear Pburke, do U compare the performance for

http://www.texascomponents.com/Tx2352a.pdf, vishay & caddock????

thx

thomas

[Peter Daniel]

I think for I/V conversion your best bet would be Riken or Caddock TF020.

[tube-lover]

Dear peter,

If I choose Koa Low ppm, 5/1000 inthe digital circuit & use Riken ( RMA or RMG ) in the I/V. Will be be the better choice?

any more advise ? peter!

thx

thomas

[Peter Daniel]

I don't have any experience with KOA resistors and they were not much mentioned on a forum either: http://www.diyaudio.com/forums/searc...der=descending

But Rikens work well in I/V stage (both with TDA1543 and in your circuit)